A winter wonderland in the River Ehen

I have just finished another visualisation of the underwater life of the River Ehen, following up my observations in Food for Thought from the River Ehen.   In that post I commented on the prominent brown biofilms that I saw on rocks which, under the microscope, turned out to be mixtures of the green alga Bulbochaete and diatoms.   I have tried to convey this in my illustration, with the long-stalked Gomphonemas risking through the mat of Bulbochaete filaments (many of which end in long hairs) and, on the left hand side, a colony of Fragilaria tenera cells, loosely attached to the green alga.   Our measurements showed a conspicuous increase in the quantity of algae present on the stream bed compared to our previous visit, though we are still puzzling about why this is the case.


The submerged world of the River Ehen, November 2014 showing diatoms growing on and around Bulbochaete: left: Fragilaria tenera, central foreground, Gomphonema truncatum, left foreground: Gomphonema acuminatum.   The Gomphonema truncatum cells are about 40 micrometres (one fortieth of a millimetre) long.

We do know that many of the stream algae found in the UK are able to grow at low temperatures and so thrive throughout the winter.   One reason why we expect the increased quantity at this time is that the grazers which feed on the algae are less active in cold weather so the ratio between algal biomass that is produced and that which is consumed decreases.   Just how effective grazers can be is illustrated by two photographs taken the following month, one of which shows even more algae present at the same site where the samples on which my picture is based were collected. The other was taken about 100 metres upstream on the same day and shows another stone covered with tiny Simuliidae larvae.   These will, in time, develop into the swarms of blackflies that can plague river users, as the adult females of many species feed on human blood.


Left: a stone from the bed of the River Ehen in December 2014 covered with Simuliidae larvae (scale bar: one centimetre) and, right, the head of a Simuliidae larva (scale bar: half a millimetre).

Of course, the abundance of Simuliidae larvae does throw some doubt on the idea that lack of grazing is primary reason for the abundance of algae.   Yet this is the first time we have seen such an abundance of Simuliidae at this particular site (which has sometimes had the greatest quantity of algae of all the sites on the Ehen that we visit) which means that we are puzzling over variability in time as well as in space.   I suspect that the long hairs on the Bulbochaete, as we know that other species with similar structures use these to secrete enzymes into the water that enable them to release phosphorus from organic molecules. My suspicion is that the wetter conditions of autumn and winter flush more of these molecules from the peaty soils of the Ennerdale catchment into the river and these, coupled with the lower grazing intensity, fuel the burst of growth that we see.


A mass of green algae (predominately Bulbochaete sp) smothering stones on the bed of the River Ehen, December 2014.   The effect of the numerous colourless hairs of the algae is to create a translucent “haze” over the top of the mass of green filaments.

Simuliidae larvae are often described as filter-feeders which attach to the substratum and have mouthparts adapted into “fans” that capture particles as they drift downstream. However, I have seen Simuliidae bent double so that they can feed directly on the benthic algae. Look at the difference in the quantity of algae between stones with and without Simuliidae, which were only about 100 metres apart.

We have been visiting the Ehen regularly now for about two years and it continues to surprise us.   Simuliidae were certainly not here in such obvious quantities at this time last year or the year before.   I suspect that we are dealing here with nothing more sinister than nature’s complex dynamics, and it makes the case, again, for a slower and more patient study of the natural world than is often possible with the present grant-awarding system (see “Slow science and streamcraft”).   Two and a half years into my explorations of the River Ehen and I’m still sometimes surprised by what I am seeing.



My earliest memory of art was a trip on a wet Saturday afternoon to the Imperial War Museum in London when I was no more than six or seven.   One picture made a huge impact on me during that visit: John Singer Sargent’s Gassed, a huge canvas (231 cm x 611 cm) depicting a line of blinded soldiers, each with a hand on the shoulder of the man in front, being led towards a field hospital.   I found the painting absolutely horrifying at the time and it fuelled nightmares for months afterwards.   That I can still remember the visit over forty years later is a testament to the power of the image.


John Singer Sargent’s Gassed (1919) at the Imperial War Museum’s Truth and Memory exhibition, December 2014.

I went back to the Imperial War Museum a few days ago to visit their Truth and Memory exhibition of art from the Great War and there it was again. I do believe that John Singer Sargent, a society portrait painter before the war, manages to achieve with realism a more visceral effect than modernists such as Nevison and Nash attained, partly because of its scale and perspectival qualities. As in the case of Kiefer (see “The fine art of asking big questions”) Sargent invites you into the horrific world that his picture depicts.

Unfortunately, the painting is not displayed to the best effect in the current show at the Imperial War Museum: the gallery is cluttered with cabinets and busts and the viewer is unable to get an unimpeded view of the whole picture.   But it is still a very moving image.   Close up, there are some surprises: behind the row of soldiers a football match is going on (an allegory of the British “playing the game” whilst the dastardly Germans resort to poisonous gas, maybe?).   Like a lot of the art on display, Gassed was produced after the hostilities, as the country started to come to terms with the horrors of the war free from the censorship that tried to present only positive images of the front whilst hostilities were ongoing.


Detail from John Singer Sargent’s Gassed (1919): a football match continues behind the injured soldiers.

I worry that fine art these days is too easily relegated to a branch of interior decoration; we buy pictures because they will look good on our walls rather than for any deep moral purpose. Gassed is not a picture that anyone would want on their wall. It is a picture to stand before and meditate, a picture that tells us a tale about human condition and one that offers up a moral lesson.   That, in fact, was the primary purpose of what we now call “fine art” until about 400 years ago.   Truth and Memory has few pictures that qualify as “beautiful” or “tasteful” and none that glorify war.   There is nothing, indeed, that you would want to hang on your living room wall. That’s what makes it so worth visiting.

What has the European Union ever done for us?

There is now less than six months to go before the next general election in the UK and I am going to write a few posts over the coming months evaluating the prospects for the environment that emerge from the political debate.   The rise of UKIP means that this is going to be an election like no other that we have experienced in the UK and, inevitably, Europe is going to be high on the agenda. Add in the inevitable concerns about the economy and the health service and the environment will probably slip down the agenda to that part of each party’s manifesto where rhetoric rules over reality.

Except that the focus on Europe and the economy means that the outcome of this election will have enormous implications for the UK’s environment.   First, most of our environmental legislation derives, ultimately, from the European Union (EU) and, second, implementing environmental legislation requires a strong, well-funded regulator.   We go into the next election campaign aware that leaving the EU is a genuine possibility and, consequently, be aware of the implications.   At this stage, of course, we don’t know what “leaving the EU” really means.   The UK could, in theory, leave the EU but remain part of the European Economic Area, members of which voluntarily adopt EU environmental legislation.   Another possibility is that we leave the EU and EEA but retain the framework of environmental law that we have inherited from the EU (because this has been transposed into UK legislation).

My view is that the environment is one of the principal beneficiaries of UK’s membership of the EU. This is partly because this is an area of policy which benefits from a joined-up approach: the state of the North Sea, for example, depends on the individual environmental policies of UK and six other countries which share its coastline, plus Switzerland (in the EEA but not the EU) and Luxembourg, both wholly or partly in the Rhine catchment.   It is also influenced by the Baltic Sea, which is bordered by a further seven countries, all but Russia EU members. The UK’s use of the North Sea requires a level of agreement amongst these countries that the EU facilitates.   This is not the only example: air pollution does not respect national boundaries either, and there are river catchments in Ireland which straddle the north-south border and so benefit from a shared approach to management.

I also believe that the EU provides a better forum for discussing and developing environmental legislation. Domestic politicians have been, rightly, focussed on the economy and health service. I do not believe that the level of protection afforded by the Water Framework Directive, for example, could have been produced by Westminster politicians working in isolation because of the amount of parliamentary time it would have required.   Watching the way that non-scientists such as Nigel Lawson have hijacked and distorted the debate on global warming in the UK also makes me sceptical about whether Westminster, alone, has the ability or integrity to evaluate new environmental legislation objectively.

I use the term “Westminster” very loosely here as the environment is one power that has been devolved to Scotland, Wales and Northern Ireland.   In practice, all four administrations are implementing the same set of EU Directives which ensures a joined-up approach.  I know, from meetings I have attended, that there is a centrifugal tendency amongst the administrations, reflecting a legitimate desire to adapt environmental policy to the different conditions of each of the UK’s four constituents. The framework of EU policy, however, provides a centripetal counterweight to these tendencies.

My worry is that our country is ill-served by its politicians with respect to environmental policy. We have a largely London-based political class, a large proportion of whom have little scientific training and many of whom have reduced “Europe” to a political football.   Differences in how Scotland and England manage the environment may appear abstract to those based in London (or Edinburgh) or subservient to a wider ideal. However, these issues take on a much larger significance to anyone who lives in the catchment of the River Tweed, for example.   What happens on the north side of the river has implications for what might happen further downstream on the south side.   The same applies to the River Foyle and many other examples around the UK.

We will, I am sure, hear much rhetoric about “global warming” in the run up to the next election. Remember that the biggest danger to the environment may be the hot air produced by the politicians themselves.